Flightless Flier

There was a research center in Des Moines, IA, with a special team of scientists. They were trying to design a perfect flying aircraft that was lightweight, strong, and fast. One of the researchers went to the head chief and proclaimed,"We have done it! We have created an aircraft with zero drag! Isn't this great?"
The chief stared at him and said plainly,"You think you created an aircraft with zero drag. Well, you obviously slept during physics class. Now go back and try again."
What's the matter?